I. Impact on Argument A. Initially makes argument seem effective B. Upon further reflection, will undermine argument with weak reasoning
C. Relying on emotion without careful consideration can result in fallacies
D. Fallacies can "feel" more convincing than logos.
II. Important Note - Be aware of possible fallacies to: A. Identify in the argument of others
B. To ensure that you do not make these mistakes in your writing III. Top Ten Logical Fallacies A. Ad Hominem1. "Against the Man"
2. Attacks another person's point of view by criticizing that person, not the issue
3. Tries to invalidate a person's ideas by revealing unrelated, past/present, personal, and ethical flaws 4. Example: "What can the priest tell us about marriage? He's never been married himself."
B. Hasty Generalizations 1. Leaps to premature conclusions - not because of evidence but because evidence is insufficient to convincingly support a claim made.
2. Example: Claim = "Burglary has increased in the neighborhood", and the person uses, as his/her only evidence, "the two houses on the block have been burglarized."
3. Error in Logic: Would have to prove this # is greater for the same time frame one year ago.
4. Prejudice is a result of "hasty generalizations." This is based on 2-3 members, sharing same characteristics.
C. Either/Or 1. "Black and White"
2. Fails to consider other options
3. Assumes there are only two options to resolving a given situation when there might be many solutions/options not yet considered.
4. Examples:
a. "If you are not part of the solution, you are part of the problem."
b. "If you love nature, then you can't possibly support industrial development " - recycling, wind, solar, biomass = industries
c. "America: Love it or leave it"
external image help-books-aj.svg_aj_ash_01.png
D. Questionable Authority 1. Abused in advertising
2. "Studies show," "Experts claim," "Surveys prove"...
3. Be suspicious of crediability when statements are never fully developed
4. Example: "Several studies show that teenagers who have low self-esteem tend to get bad grades."
E. False Analogy 1. Two things are alike in some ways; therefore, the two things are alike in all ways
external image applesoranges.jpg
2. Purpose = overlook significant differences
3. Examples:
a. A student dislikes teacher's strict regimented classroom tatics, and therefore says, "the classroom is like Hitler's Third Reich." The two do not parallel unless teacher hired secret police and put people
in concentration camps.
b. "It isn't fair that I can't write on anything I want, anyway I want. Nobody tells Amy Tan or Stephen King how to write."
external image scared-black-cat.gif
F. Post Hoc 1. "After the fact, therefore because of the fact"
2. A.K.A. "False Cause"
3. Just because one event follows another does not mean the first event caused the second.
4. Superstitions
5. Example:
a. Effect = tripping and falling
b. Cause = sudden appearance of black cat
c. No logical cause = slippery; not paying attention
G. Red Herring
external image redherring.jpg
1. Arguments that make attempts to deliberately redirect the audience's attention to something unrelated to the core issue.
2. Change the topic
3. Why is the speaker changing the topic?
4. Example: After listening to a voter's concern that a community high school needs to receive major funds to upgrade facilities, a candidate responds, "I understand your concerns and have asked the school board to review its policies.
5. Error in Logic: throws a "red herring" by changing subject from inadequate facilities to board's educational policies
H. Slippery Slope 1. Arguer predicts that taking a first step will lead to a second, usually undesirable step ( A = B = C = D, etc.)
external image Slippery-Slope.png
2. Simplistic
3. Must provide evidence will happen
4. Example: "If medical researchers continue to increase human longevity, then the human population will soar out of control, mass famine will occur, the global economy will collapse, and the survival of the species will be threatened."
I. Non Sequitur 1. "It does not follow"
2. Presenting as evidence ideas that have no logical connection to each other
3. Examples:
a. Bridgeville School is a lot bigger than Rawlings Memorial, and so Bridgeville is a much better school.
b. Nellie is obsessed with basketball because she attends games every weekend.
J. Begging the Question 1. An argument that begs the question asks the reader to simply accept the conclusion without providing real evidence
2. Examples:
a. Chocolate is healthy because it grows on trees. (Conclusion made with lack of support)
b. Chocolate is healthy because it is good for you. (Restates the conclusion)
3. Ask: What is your support for that premise or what does that have to do with anything?
4. Circular Reasoning
5. Example: Mr. Jones is a good communicator because he speaks effectively.
I. Impact on Argument
A. Initially makes argument seem effective
B. Upon further reflection, will undermine argument with weak reasoning
C. Relying on emotion without careful consideration can result in fallacies
D. Fallacies can "feel" more convincing than logos.
II. Important Note - Be aware of possible fallacies to:
A. Identify in the argument of others
B. To ensure that you do not make these mistakes in your writing
III. Top Ten Logical Fallacies
A. Ad Hominem1. "Against the Man"
2. Attacks another person's point of view by criticizing that person, not the issue
3. Tries to invalidate a person's ideas by revealing unrelated, past/present, personal, and ethical flaws
4. Example: "What can the priest tell us about marriage? He's never been married himself."
B. Hasty Generalizations
1. Leaps to premature conclusions - not because of evidence but because evidence is insufficient to convincingly support a claim made.
2. Example: Claim = "Burglary has increased in the neighborhood", and the person uses, as his/her only evidence, "the two houses on the block have been burglarized."
3. Error in Logic: Would have to prove this # is greater for the same time frame one year ago.
4. Prejudice is a result of "hasty generalizations." This is based on 2-3 members, sharing same characteristics.
C. Either/Or
1. "Black and White"
2. Fails to consider other options
3. Assumes there are only two options to resolving a given situation when there might be many solutions/options not yet considered.
4. Examples:
a. "If you are not part of the solution, you are part of the problem."
b. "If you love nature, then you can't possibly support industrial development " - recycling, wind, solar, biomass = industries
c. "America: Love it or leave it"
1. Abused in advertising
2. "Studies show," "Experts claim," "Surveys prove"...
3. Be suspicious of crediability when statements are never fully developed
4. Example: "Several studies show that teenagers who have low self-esteem tend to get bad grades."
E. False Analogy
1. Two things are alike in some ways; therefore, the two things are alike in all ways
2. Purpose = overlook significant differences
3. Examples:
a. A student dislikes teacher's strict regimented classroom tatics, and therefore says, "the classroom is like Hitler's Third Reich." The two do not parallel unless teacher hired secret police and put people
in concentration camps.
b. "It isn't fair that I can't write on anything I want, anyway I want. Nobody tells Amy Tan or Stephen King how to write."
F. Post Hoc
1. "After the fact, therefore because of the fact"
2. A.K.A. "False Cause"
3. Just because one event follows another does not mean the first event caused the second.
4. Superstitions
5. Example:
a. Effect = tripping and falling
b. Cause = sudden appearance of black cat
c. No logical cause = slippery; not paying attention
G. Red Herring
1. Arguments that make attempts to deliberately redirect the audience's attention to something unrelated to the core issue.
2. Change the topic
3. Why is the speaker changing the topic?
4. Example: After listening to a voter's concern that a community high school needs to receive major funds to upgrade facilities, a candidate responds, "I understand your concerns and have asked the school board to review its policies.
5. Error in Logic: throws a "red herring" by changing subject from inadequate facilities to board's educational policies
H. Slippery Slope
1. Arguer predicts that taking a first step will lead to a second, usually undesirable step ( A = B = C = D, etc.)
2. Simplistic
3. Must provide evidence will happen
4. Example: "If medical researchers continue to increase human longevity, then the human population will soar out of control, mass famine will occur, the global economy will collapse, and the survival of the species will be threatened."
I. Non Sequitur
1. "It does not follow"
2. Presenting as evidence ideas that have no logical connection to each other
3. Examples:
a. Bridgeville School is a lot bigger than Rawlings Memorial, and so Bridgeville is a much better school.
b. Nellie is obsessed with basketball because she attends games every weekend.
J. Begging the Question
1. An argument that begs the question asks the reader to simply accept the conclusion without providing real evidence
2. Examples:
a. Chocolate is healthy because it grows on trees. (Conclusion made with lack of support)
b. Chocolate is healthy because it is good for you. (Restates the conclusion)
3. Ask: What is your support for that premise or what does that have to do with anything?
4. Circular Reasoning
5. Example: Mr. Jones is a good communicator because he speaks effectively.